1977 Dan-Air Boeing 707 crash: Difference between revisions

Tests were conducted to determine whether or not the loss of a single stabilizer was a recoverable situation, and it was determined that recovery would have been possible with action on behalf of the pilots in the form of nose up trim. The wreckage recovered revealed that the elevator trim should have been sufficient to save the aircraft, but further analysis concluded that the failure of the stabilizer was violent enough to fracture the vertical trim jackscrew, which would have resulted in the remaining horizontal stabilizer pitching into a nose down trim position.

The crack found in the failed stabiliser after the accident was thought by investigators unlikely to have been detectable using normal testing means, such as fluorescent dye. It was also thought that the crack had been present for at least 6,000 flight hours before the accident, and before the aircraft had been acquired by Dan-Air from Pan Am.

Inspections of the Boeing 707-300 fleet, made as a result of the crash, found another 38 aircraft with similar cracks.<ref name="Cheney">[http://www.tc.gc.ca/eng/civilaviation/publications/tp185-2-07-maintenance-3674.htm "Ageing Airplane Rulemaking", Blake Cheney (Acting Manager, Domestic Regulations, Regulatory Standards, Aircraft Certification, Civil Aviation, Transport Canada)] retrieved 28 August 2012 {{Wayback|df=yes|url=http://www.tc.gc.ca/eng/civilaviation/publications/tp185-2-07-maintenance-3674.htm|date =20131224175844}}</ref>